With the rapid development of frequency converter technology, frequency control technology has become the mainstream in various motor application schemes.

Frequency converters are widely used. They are divided into low-voltage frequency converters and medium and high-voltage frequency converters according to their voltage levels. The purpose and demand of applications in various industries are different, such as petroleum, chemical, steel, metallurgy, steel rolling line, construction, power, mining, transportation, cement, paper industry, electronic manufacturing industry, etc.

Next, to introduce the braking force and protection function of the frequency converter:

The so-called braking force of the frequency converter is the energy regenerated from the motor stored in the filter capacitor of the frequency converter. Due to the relationship between the capacity of the capacitor and the withstand voltage, the regenerative braking force of the general inverter is about 10% ~ 20% of the rated torque. If the optional brake unit is used, it can reach 50% ~ 100%.

Protection functions can be divided into the following two categories:

1. After the abnormal state is detected, the corrective action will be carried out automatically, such as over-current stall prevention and regeneration overvoltage stall prevention.

2. After detecting the abnormality, the PWM control signal of power semiconductor device is blocked to stop the motor automatically. Such as over-current cut-off, regeneration overvoltage cut-off, semiconductor cooling fan overheating and instantaneous power failure protection.

The working principle of frequency converter is relatively complex, so there are many things designed in the process of use, so the corresponding protection of nature is to protect the good function of the inverter quality.